4l80e shifts 1st to 2nd no 3rd and lockup

SOURCE: 93 gmc sierra not shifting into 3rd gear

i dont know how to fix it so go **** yourself!!!!

SOURCE: 95 GMC Jimmy 4L60E no 2nd or OD 4L60E

You might want to try this if its got a kick down cable unhook it from throutle body and pull it out as far as you can and let it snap back, do this a few of times, sometimes a valve gets hung up inside valve body of trans. and won't let it shift. If that don't help you may have to pull pan to dislodge it if thats the problem. chk. the plug on trans. (Its a 4 wire white plug) with test light with key on to see if there is power down there one will be hot, thats for overdrive, now on top of intake in front throutle body there is a sending unit that looks like a temp. sending unit with a 2 wire plug on it that sends a signial down to that plug when engine gets to temp. to let it shift to overdrive. Maybe this will help, or give you some ideas.

SOURCE: 4L80E WITH DTC PO757A 2-3 SHIFT SOLENOID VALVE

it turned out to be the stall in the converter. i needed to install a low stall and the code never came back.

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SOURCE: The transmission is shifting hard going from 1st

rec check fluid first. If trans fluid hasn't been changed in last 30,000 miles change fluid, filter and pan gasket. At that time inspect for foreign materials in bottom of pan or on magnet if you have one. If truck has over 100K and fluid was never changed you may have more problems if changing the fluid.

Harvey N Tawatao

• 3854 Answers
• Posted on Sep 21, 2010

SOURCE: transmision starts out in 1st

Sounds like your transmission is in limp mode. This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

The other from what you described, trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Thank you for using fixya and have your Safari scanned for the DTC codes that would indicate what issues your transmission is having to put you in to limp mode.